Seventy years ago, A. N. Whitehead wrote that “the art of life is first to be alive, secondly to be alive in a satisfactory way, and thirdly to acquire an increase in satisfaction.” Some contemporary evolutionary theorists have maintained that only the individual who is selfish in every respect will survive and thrive in what Whitehead called the art of life. Elliott Sober and David Sloan Wilson beg to differ.

In their widely influential book, Unto Others: The Evolution and Psychology of Unselfish Behavior (1998), Sober and Wilson use research and reason to reshuffle the biological and psychological cards when addressing prevailing scientific assumptions about altruism and egoism. The hand they play makes their book, as Jeffrey Schloss proclaims, “one of the most controversial and significant books to emerge on human evolution, and on altruism, since the sociobiological revolution.”

Because this book has exerted broad influence in the few years since being published, I offer this summary review to those wanting to keep abreast of significant developments related to science and religion concerns.

Sober and Wilson argue that evolutionary theory solves problems related to biological and psychological egoism and altruism. The authors state succinctly the book’s agenda by claiming that “the case for evolutionary altruism requires showing that group selection has been an important force in evolution. The case for psychological altruism requires showing that an ultimate concern for the welfare of others is among the psychological mechanisms that evolve to motivate adaptive behavior” (6-7).

The focal point of the evolutionary solution they propose is group selection theory. In short, the theory says that individuals sometimes act altruistically toward fellow members within the group of which they are a part so that the group as a whole survives and thrives. Group selection theory, however, does not lead the authors “to paint a rosy picture of universal benevolence.” Instead, “group selection favors within group niceness and between group nastiness” (9).

Group selection theory is actually not a new theory. Until a number of biologists attacked the supposition in the 1960s, the theory had many adherents. In recent times, however, genetic individualism has prevailed. In turn, biological egoism has become orthodoxy in evolutionary biology; most biologists have regarded non-kin altruism as illusory. When individuals help others, so the current thinking goes, they do so exclusively either to receive benefits in return or promote their own genetic self-interest.

Sober and Wilson offer their book to report and extend “a transition in evolutionary thought” that accepts group selection as a biological basis for affirming altruism, a transition “that is already in full swing” (7). “Many evolutionary biologists continue to play the ‘group selection is dead’ song from the 1960s with the same fondness they have for the Beatles,” the authors wryly comment. “Little wonder then, that scholars from other disciplines who are interested in evolution have heard almost nothing about these scientific developments” (51).

Psychological altruism has also fallen on hard times. After all, if evolutionary altruism is absent in nature, many believe that there is no good reason to affirm psychological altruism as truly present in human nature. The influence that psychological egoist theory exerts, however, “far outreaches the evidence that has been mustered on its behalf,” argue the authors (2). “The idea that human behavior is governed entirely by self-interest and that altruistic motives don’t exist has never been supported by either a coherent theory or by a crisp and decisive set of observations” (8).

The book divides into two major parts. In the first, the author’s “task is show the behaviors that benefit others at the expense of self can evolve.” In the second part, their “task is to understand psychological mechanisms that evolve to motivate these adaptive behaviors” (17-18).

The basic point of the first chapter, “Altruism as a Biological Concept,” is that “altruism can evolve to the extent that altruists and non-altruists become concentrated in different groups” (26). This concentration allows for altruism to be maladaptive with respect to individual selection but adaptive with respect to group selection. “To be sufficient, the differential fitness of groups (the force favoring the altruist) must be strong enough to counter the differential fitness of individuals within groups (the force favoring the selfish types)” (26). In this way, altruism can evolve as selection occurs through groups. (The authors define a group as “a set of individuals that influence each other’s fitness with respect to a certain trait, but not the fitness of those outside the group” [92]).

The authors note that “despite the importance of motives in conventional definitions, evolutionary biologists define altruism entirely in terms of survival and reproduction” (17). This means that a behavior is altruistic when it increases the survival and reproductive fitness of others and decreases the survival and reproductive fitness of the actor.

Because of what the authors call “the averaging fallacy,” a problem arises when comparing altruism and egoism. The problem is that “a single trait can appear to be altruistic or selfish depending on whether fitnesses are compared within groups or averaged across groups and then compared” (32). “When one trait is more fit than another,” explain the authors, “this may be due to pure individual selection, to pure group selection, or to a mixture of the two. The description of the effect fails to specify what the causes were” (33). Sober and Wilson boldly assert that “the entire history of evolutionary biology in the last three decades, in which group selection was rejected while other frameworks became the foundation for the study of social behavior, would have been different if the averaging fallacy had been avoided” (157).

The authors claim that the “evolutionary study of social behavior during the last thirty years has reflected a massive confusion between alternative theories that evoke different processes, on the one hand, and alternative perspectives that view the same process in different ways, on the other” (57). The authors believe that it is now possible to offer, as the title of the second chapter puts it, “A Unified Evolutionary Theory of Social Behavior.” The key to this unified theory “is to achieve a legitimate pluralism in which the different processes are distinguished from ways of viewing the same process” (57).

To the end of achieving this legitimate pluralism, the authors consider several major biological theories, including kin selection, fitness theory, evolutionary game theory, selfish gene theory, and tit-for-tat strategies. These “theories were launched as alternatives to group selection,” argue Sober and Wilson, but they are “merely different ways of looking a evolution in group structured populations” (98). At the very least, the authors contend, group selection, as one selection mechanism level (“multi-level selection”), must be included in evolutionary biology’s pluralist family of theories.

The authors single out kin selection theory (which is the idea that individuals are only altruistic toward those to whom they are genetically related and therefore those who will pass on their genes) for particular appraisal. “For all its insights,” they maintain, “kin selection has led to the constricted view that genealogical related is the one and only mechanism for the evolution of altruism; because of this theory’s widespread acceptance, altruism has eclipsed adaptation as the central question of social biology. Multi-level selection theory expands the view by focusing on adaptation as the central question and examining the fundamental ingredients of natural selection … that are required for adaptations to evolve at all levels of the biological hierarchy. Altruism can be understood only in this context of broader framework” (158). “Replacing kin selection theory with multi-level selection theory,” remark the authors, “is like shutting off the spotlight and illuminating the entire stage” (332).

In the third chapter, the authors address directly how multi-level selection relates with adaptation. They offer a procedure that involves determining what would evolve if either (1) group selection or (2) individual selection were the only evolutionary force, and then (3) examining the basic ingredients of natural selection at each level of selection. “To the extent that a trait has evolved by natural selection,” explain Sober and Wilson, “steps one and two bracket the possibilities, with real populations lying somewhere in between. The third step involves examining the fundamental ingredients of natural selection at each level to see where the population is likely to lie between the two extremes of pure between group and pure within group selection. … This three step procedure makes it clear that group selection can be a significant evolutionary force in ways that do not require groups of genetic relatives” (157).

When following this three-step procedure, multi-level selection “furnishes a framework for understanding the evolution of our own species” (102). “When we view our own species through the lenses of multi-level selection theory,” the authors conclude, “we discover that human behavior cannot be placed, in its entirety, at one point on the continuum from pure group selection to pure individual selection” (130).

Sober and Wilson apply the theory of group selection to human evolution and behavior. After all, multi-level theory should also demand that human groups be evaluated in terms of the fundamental ingredients of natural selection. The authors conclude that “human social interactions among unrelated individuals are anything but random, and our ability to learn and to change our behavior according to what we learn provides a powerful mechanism for evolution of altruism and other group advantageous behaviors” (142).

In the final chapter of the book’s first part, “Human Groups as Adaptive Units,” the authors address specific human cultures. These cultures were evaluated and analyzed by a survey from the Human Relations Area Files, which is an anthropological database designed to facilitate cross-cultural comparisons. This intriguing chapter provides further strength to the group selection theory. “As strange as it may seem against the background of individualism,” conclude the authors, “the concept of human groups as adaptive units may be supported not only by evolutionary theory but by the bulk of empirical information on human social groups in all cultures around the world” (193). The authors summarize the chapter and the first part the book by saying that “at the behavioral level, it is likely that much of what people have evolved to do is for the benefit of the group” (194).

In the second part of Unto Others, the authors discuss altruism as an issue in psychology. They begin by defining terms. Psychological egoism is defined as the theory that all our ultimate desires are self-directed. Psychological altruism maintains that we sometimes care about others for their own sake. The two theories agree that people sometimes desire that others do well. However, note the authors, “the debate concerns whether such desires are always instrumental or are sometimes ultimate” (201).

The mind resides at the forefront of the altruism and psychology discussion. An evolutionary perspective on human behavior, claim the authors, requires one to “regard the human mind as a proximate mechanism for causing organisms to produce adaptive behaviors” (200). In particular, “beliefs and desires are items in the mind that produce behavior” (208). Yet, argue Sober and Wilson, “an organism need not have a mind to be an evolutionary altruist.” Furthermore, “you don’t have to beliefs and desires to be evolutionary altruist” (202).

The authors summarize their thought by saying that, “in the debate between egoism and altruism, everyone agrees that some of the desires that people have are egoistic in character. We have suggested that individuals are able to have these uncontroversial desires only if they have the concept of an ‘I.’ Being able to use this concept does not require self-awareness, but merely self-recognition. Organisms that form perpetual beliefs that represent objects in their environment in terms of how those objects are related to self may plausibly be thought of as employing the concept of ‘I'” (216-17).

In one of the most helpful and provocative chapters, Sober and Wilson examine, as the chapter title puts it, “Three Theories of Motivation.” The three theories they have in mind are hedonism, egoism, and altruism.

The authors define hedonism as the theory that “the only ultimate desires that people have are the desires to obtain pleasure and avoid pain.” “The distinctive feature of hedonism,” the authors add, “is that it says that ultimate desires are always solipsistic” (224).

Egoism is defined as the theory that “the only ultimate goals an individual has are self-directed; people desire their own well-being, and nothing else, as end in itself” (224). The point is made that, although all hedonists are egoists, not all egoists are hedonists. After all, an egoist may desire pain for herself and avoid experiencing personal pleasure.

Altruism is defined as the theory that “people sometimes care about the welfare of others as an end in itself.” The authors quickly note that they regard altruism as “part of the pluralistic theory of motivation that maintains that people have ultimate desires about others as well as about themselves.” This means that their version of altruism “is quite compatible with the existence of widespread selfishness” (228). However, pluralism and egoism, as they define them, are incompatible, because egoism claims that people ultimately desire nothing but their own well-being.

The authors remark that their theory of pluralistic motivation can be said to describe an organism’s behavior in two ways. “One possibility is that some of the actions the organism performs are caused solely by altruistic ultimate motives while others are caused just by egoistic ultimate motives.” Another possibility is that an organism’s actions “are caused by both altruistic and egoistic ultimate motives” (308).

Sober and Wilson examine the common practice of equating altruism and morality. They make several important claims. They claim that, first, morality does not always require one to sacrifice self-interest for the sake of others. Second, being motivated by an altruistic desire is not the same as being motivated by a moral principle. Third, altruistically motivated actions can be morally wrong, while selfishly motivated actions may be morally required. Finally, altruism, as the authors understand it, does not require that one care about the welfare of another for purely other-directed reasons: “the hypothesis does not rule out the possibility that instances of helping are sometimes or even always accompanied by ultimate motives that are self-directed” (246).

Chapters eight and nine are less provocative than previous chapters. The authors examine psychological evidence and determine that this evidence does not prove conclusively whether or not human beings ever have altruistic ultimate motives. The evidence, however, does not prove the egoist hypothesis either. The main reason that psychological evidence does not wholly confirm the truth of egoism or altruism (or pluralism) is that, according to the authors, introspection does not inerrantly reveal to us our ultimate desires. The authors draw the same conclusion when discussing the philosophical arguments regarding egoism and altruism (or pluralism) as they did when discussing the psychological evidence for the debate. That is, they conclude that philosophical arguments are inconclusive.

The book’s final chapter shows how evolutionary considerations bear on the question of psychological motivation. The authors intrepidly claim that “no version of egoism is plausible for organisms such as ourselves” (297), by which they apparently mean that egoism, when defined as the theory that the only ultimate goals an individual ever has are self-directed, is not plausible as an explanation of human behavior. At the center of the chapter’s discussion is the parent-child relationship. “We can conjecture that human parents typically want their children to do well—to live rather than die, to be healthy rather than sick, and so on,” state Sober and Wilson. “The question we will address is whether this desire is merely an instrumental desire in the service in some egoistic ultimate goal, or part of a pluralistic motivational system in which there is an ultimate altruistic concern for the child’s welfare. We will argue that there are evolutionary reasons to expect motivational pluralism to be the proximate mechanism for producing parental care in our species” (302). In fact, “parental care would be more reliably produced by purely altruistic motives than by purely hedonistic motives” (319).

In a chapter subsection entitled, “A Continuum of Cognitive Capacities,” the authors note that humans and other organisms are cognitively limited. The authors lay out a continuum in which a simple conditionable organism at one end of the continuum has no, or virtually no, cognitive abilities. At the other end of the continuum is the hypothetical individual with unlimited cognitive abilities. “Let us suppose, for the sake of argument, that cognition began to evolve in organisms that already had the capacity to experience pleasure and pain,” the authors venture. “Even if the first organisms that had desires were hedonists, what circumstances could make it selectively advantageous for organisms to depart from the dictates of hedonism by having some of their behaviors regulated by purely altruistic motives?” (311) The answer given is that those organisms with greater cognitive resources might be motivated to be pluralistically motivated. In fact, the authors eventually contend that “pluralism was probably available ancestrally, if hedonism was” (322).

Those organisms with sophisticated cognitive abilities have greater capacity for, and reason to, act upon pluralistic motivations. “The obvious evolutionary strategy for an organism that can form reliable beliefs about its own body and about the welfare of relevant others,” conclude the authors, “is for it to set its eyes on the prize.” The organism’s “ultimate desire should include a concern for something that is far more important in terms of evolutionary success than the states of its own consciousness” (324).

The authors conclude their discussion of how psychological altruism evolved by tying together the example of the parent-child relationship with group selection theory. “Just as motivational pluralism is a plausible design solution for the problem of getting parents to take care of their children, so pluralism is a plausible design solution for the problem of getting members of a group to take care of each other” (326). In short, “evolution has made us motivational pluralists, not egoists or hedonists” (327).